topic Re: Four Axis milling doesn't work right in Fusion Support Forum

Four Axis milling doesn't work right

abendaniel25 — Thu, 22 Dec 2022 21:00:01 GMT

I have a Tormach PCNC1100 and recently added an additional fourth "A" axis.

The axis works great with manual control, but when attempting to program the machine with Fusion360 it doesn't create the correct toolpaths. In my NC Program > Configuration > Rotary table axis, I have an X axis. Is this correct?

I created a part and made some toolpaths to mill it.

However, when I post-process with the default Tormach Pathpilot post-processor (which states it supports 4-axis milling) it creates some extremely strange G-Code. It looks like it's attempting to follow the rotary toolpaths as though the tool was the thing that was rotating (not the part/stock). In the simulation of the toolpaths this appears this is the case.

How do I tell Fusion that the part is the one that is rotating and not the tool?

Re: Four Axis milling doesn't work right

kellings — Fri, 23 Dec 2022 01:03:41 GMT

Hi @abendaniel25 It's doing the correct thing.

You could create a machine and simulate that where you would see the part rotate and the spindle stay stationary. In the simulation without the machine, the spindle will rotate but the part will stay stationary. This will run on the machine just fine.

Re: Four Axis milling doesn't work right

abendaniel25 — Fri, 23 Dec 2022 01:40:45 GMT

It's more than just that, the G-Code is weird too.

This is what Tormach Pathpilot shows, which is definitely wrong. It tries to use the Z and Y axis to trace the circular spiral, even though the A axis turns as well.

Re: Four Axis milling doesn't work right

abendaniel25 — Fri, 23 Dec 2022 19:09:06 GMT

Apparently, the toolpaths shown are correct. I tried (very slowly) to use them and it did end up doing the right thing. I guess Pathpilot is just really weird about showing 4-axis programs.